This invention relates to a lock mechanism, and particularly to a lock mechanism of the dead bolt variety.
Prior dead bolt lock mechanisms include a dead bolt which can be moved from a retracted to an extended position. The exterior of the door includes a keyed lock cylinder which is operable by means of a key to move the dead bolt from its retracted to its extended position. Often on the inside of the door there is a thumb turn which can be rotated to move the dead bolt between its opened and closed positions.
One disadvantage of prior dead bolt lock systems is that the dead bolt can only be moved to its extended or locked position from outside the door by means of a key. Thus, with present locks, a person must locate and use a key in order to lock the dead bolt from the outside.